Technical systems are all types of technical devices and systems both arranged individually and within a data processing network, for example, via a field bus. In the case of industrial applications these include individual operating resources, for example, drives and processing machines. However, a technical system can also be a production unit in which an overall technical process is operated using locally distributed operating means, for example a chemical unit or a production line. Technical systems are controlled and operated using specific digital data processing systems, also referred to as automation components. In such a system on the one hand there are components used for direct control of the technical system, i.e. Programmable Logic Controllers PLC. In order to reduce the load on these controllers, automation systems have further specific devices, which form an interface for operating personnel. These are referred to as control and monitoring devices, in short B+B, as BETE devices or also as HMI devices (Human Machine Interface devices).
The term HMI device is a generic term covering all components associated with this group of devices. One example is operator panels or in short OPs. These can be stationary or mobile. HMI devices are used in networked automation as aids for operating personnel so that they can display and control process data of the technical system to be controlled. This function is referred to as Supervisor Control and Data Acquisition (SCADA). To this end, the HMI device generally has specific hardware. In other words it has a touch screen for example and is specifically shielded from environmental influences. Specific software is also executed therein. This provides functions which enhance user-friendliness, quality and safety of operation by an operator. Thus HMI devices can be used to visualize, control, configure and generate interactive process maps of the technical system to be operated. On the one hand this allows the selective display of responses of the technical system, generally in the form of measured values and messages. On the other hand the customized predefinition of control operations and data inputs allows the technical system to be switched to required states.
HMI devices are frequently permanently integrated, for example in the form of terminals, as stationary components in an automation system. Such terminals are then generally connected permanently to the automation system via cable connections. If these terminals are in the form of handheld devices, their radius of action is limited by a connecting cable. In many instances this ensures that an operator can only carry out safety-relevant operations in direct proximity to the technical system or at least when there is adequate visual contact.
However the situation is different when an HMI device is in the form of a mobile control and monitoring device. Such a mobile control and monitoring device can for example be connected to the automation system or the automation components via a radio link over a long range. In such an instance the possibility of an operator using a mobile control and monitoring device moving so far from an associated technical system that safety-relevant operations are carried out from a distance that is not permitted per se. In such an instance personnel safety would not be guaranteed.
In order to avoid control of the automation system by the control and monitoring device from a distance that is not permitted, it is advantageous to localize the control and monitoring device and depending on its position to enable or disable safety-relevant operations of the technical system. To this end the HMI system can also be provided with evaluation means for managing an active operating area around the technical system. The localization means evaluate the distance between the mobile control and monitoring device and the technical system in order to be able to detect whether the mobile control and monitoring device is located inside the active operating area.
The distance can be measured in this case for example with the aid of the contactless data transmission link, which connects the automation components and the mobile control and monitoring device together for data purposes.
In order to localize the distance determination, the mobile control and monitoring device can be equipped with sending and receiving means, which transmit an interrogation signal and from a resulting radio response signal received, the distance or the absolute position of the mobile control and monitoring device can be determined.
Interrogation and radio response signals are typically radar signals. The radio response signal can for example arise from a reflection of the interrogation signal from a reflecting object. Reflecting objects are for example transponder devices, which generate and transmit a modulated radio response signal as response to a received interrogation signal. Such a transponder device can for example be attached to the technical system, with the distance between a mobile control and monitoring device and the technical system being able to be determined with the aid of received radio response signals.
DE 103 43 251 describes an HMI system with a manual device for enabling or disabling safety-relevant operations of the technical system and means for localizing the mobile control and monitoring device. Evaluation means in the control and monitoring device activate the automation components for safety-relevant operations of the technical system via the control and monitoring device only when the manual device is enabled and the locating means detect that the mobile control and monitoring device is localized inside the active operating area.
EP 1 672 380 describes an HMI system with integrated transmitter and receiver concept. The control and monitoring system comprises transmitting and receiving means to localize the mobile control and monitoring device. The localization action allows an active operating area to be managed with the aid of evaluation means. The evaluation means activate the automation components for safety-relevant operations when the control and monitoring device is located inside the active area. The transmitting and receiving means are developed for the simultaneous transmission and reception of radio signals and are integrated into a single antenna module for the transponder device or the mobile control and monitoring device in each case.